Mixing and distribution device for fixing paste, particularly for multicomponent bone cement

ABSTRACT

A mixing and distribution device for fixing paste, for multicomponent bone cement, comprising a box-like body that forms internally a receptacle closed in an upper region by a detachable and fluid-tight lid, inside which devices for mixing components of the fixing paste are accommodated and are coupled to a piston that forms a venting chamber toward the lid and a mixing chamber toward the bottom of the receptacle; the mixing chamber is connected to a channel for distributing bone cement, controlled by valve devices, and the venting chamber is connected to a venting channel associated with suction devices. The mixing devices are constituted by longitudinally elongated mixing blades arranged so as to slide within complementary through slots formed in the piston; a rotation pivot is locked coaxially on the piston and is arranged so that it can slide through a corresponding fluid-tight hole formed in the lid.

TECHNICAL FIELD

The present invention relates to a mixing and distribution device forfixing paste, particularly for multicomponent bone cement.

BACKGROUND ART

Adhesives, adhesive pastes and fixing pastes in general are currentlyused in many fields to mutually fix two parts. These products are oftenproduced by mixing two different components, which form the finalproduct by reacting.

The use of these products can cause several problems, such as forexample the release of toxic gases during mixing, rapid drying of theproduct once it has formed, difficulty in applying it to the parts to bebonded, et cetera.

One of the fields in which the use of this product is particularlydelicate is orthopedic surgery.

In this field it is in fact necessary to replace certain bonecomponents, such as for example the head of the femur and/or thecotyloid cavity that engages the head in the pelvis, with artificialprostheses made of the most disparate materials, especially metallicones, but also plastic materials or materials derived from ceramic (forexample porcelain).

Alongside the problem of replacement, there is the fundamental need tofix said artificial prostheses as rigidly as possible to the referencebone.

Substantially two approaches are used to achieve this fixation.

The first approach implies coupling the prosthesis to the reference boneby way of mechanical connections such as screws, cerclages, et cetera,while the second approach, which is the one most widely used at present,provides for adhesive fixing elements.

This second approach is always used in any case when, after a certaintime, the mechanical connections fail without the possibility ofrestoring them or replacing them with other mechanical fixations.

As regards this second approach, an acrylic-based cement ispredominantly used at present.

The acrylic cement currently used is obtained from the combination oftwo components: one in powder form (usually a polymethyl methacrylate)and one in liquid form (usually a methyl or butyl methacrylate or acombination thereof), in specific proportions, which are placed inmutual contact.

The preparation and subsequent use of this cement, however, hasdrawbacks.

Combining these two components in fact currently entails some problemsin use.

First of all, this combination produces a chemical reaction thatgenerates toxic and carcinogenic vapors.

Further, the mixing of these two components must occur in relativelyshort times in order to avoid the drying reaction.

Moreover, mixing must occur so that no air (or gas) bubbles form inside,since said bubbles, once in place, reduce the mechanical strength of thecement and can also cause contaminations and infections.

Secondly, the cement obtained from this combination must sometimes beintroduced in cavities that are difficult to fill, with the risk ofleaving residual regions without cement, with an obvious reduction inmechanical strength.

Currently, all the devices used to mix these components and distributethe cement in the affected region have a common structure and operatingprinciple.

Basically, these devices comprise a container in which the twocomponents whose combination will produce the cement are introduced bymeans of various methods.

A piston or other variously shaped element, connected to the outside andclosed by means of sealing gaskets, is arranged inside said container.

A more or less high vacuum can be produced inside the container by usinga conventional manual or electric suction pump.

Once almost all the air is eliminated (if suction is used), the rotaryor pressing motion of said piston produces the mixing of the twocomponents.

In this manner, the resulting toxic gas is not dispersed into theenvironment; moreover, fewer bubbles are present in the compound becausemixing occurs almost in the absence of air.

Once this step has ended, the container is usually opened (althoughthere are rather complicated and expensive “closed cycle” solutions) inorder to remove the internal piston and collect the resulting cementpaste.

This operation can be performed in several manners, including manualgathering of the cement paste, manipulating it so as to obtain theintended consistency and shape, and then inserting it in the bonecavity.

As an alternative, it is possible to pour the paste, if it is leftliquid enough, directly into the bone cavity by means of the containeritself.

Moreover, it is possible to insert a piston in the container, convertingit into a syringe and making the cement paste flow out through a nozzlearranged at the base of the container into the bone cavity to be filled.

These devices in any case have various drawbacks in different respects.

One of these drawbacks is that one is normally forced to reopen thecontainer, thus releasing into the environment the residual gasgenerated during the mixing of the two components.

Moreover, when the mixing element (for example a rotating spatula) thatis present inside the container is extracted in order to draw the pastefrom the container, it carries away part of the paste that remainsattached to it.

Further, using these devices requires several manual operations that areoften difficult and time-consuming and are always rather laborious.

Another drawback is the complexity and size of the elements that composethese devices, which do not allow easy and immediately understandableuse on the part of nursing staff and of the physician who must positionand introduce the cement in the cavity.

The problem of the release of the gas produced by the combination of thetwo components of the cement is solved by the previously mentioned“closed cycle” devices, but these devices are very complicated, almostalways bulky, and expensive.

The complexity of these devices does not allow their economicallyconvenient disposable use, which is an increasingly requiredcharacteristic for surgical instruments in order to avoid thesterilization costs and the unavoidable possible residual risks oftransmission of infectious diseases.

One solution that substantially solves the problems noted earlier isdisclosed in Italian patent application No. PD 2002 A 284 filed by thissame Applicant.

This application discloses a mixing and distribution device formulticomponent bone cement that comprises a box-like body that formsinside it a cylindrical receptacle that is closed in an upper region bya removable fluid-tight lid and inside which a mixing/distribution screwfeeder is accommodated.

A piston is coaxially arranged between the screw feeder and the lid andis associated with movement means. Said piston forms, inside thereceptacle, on opposite sides with respect to its ends, a ventingchamber toward the lid and a mixing chamber toward the bottom of thereceptacle.

The mixing chamber and the venting chamber are connected respectively toa channel for distributing bone cement, which is controlled by firstvalve means, such as a plug valve, and to a venting channel, which iscontrolled by second valve means, such as a second plug valve.

The venting channel and the distribution channel can be associatedfunctionally with means for producing vacuum, such as a vacuum pump.

The screw feeder can be associated with rotation means, such as anelectric motor, by way of fixing lugs.

The vacuum pump allows to draw air and gas from the receptacle duringthe various steps for mixing and distributing the cement.

With this device there is no leakage or escape of toxic gas during themixing of the components of the cement or in the subsequent steps, sinceany gas is aspirated continuously. The mixture is thus obtained in apractically airless environment, thus avoiding the formation of bubblesof air or gas.

All the resulting cement is used, since the rotation and thrust of thescrew feeder tend to propel it out until it is depleted.

The unused fraction of cement, once the valves have closed again, can beleft inside the box-like body and can be eliminated together with thecontainer without producing environmental contamination.

Although this device solves most of the problems of known types, it isnot free from drawbacks.

An important characteristic of these devices is that it must be possiblefor the health worker who uses them to handle them with a single handduring distribution of the cement paste on the part to be fixed; theother hand is in fact often busy with other surgical instruments.

The described device instead cannot be handled easily with a singlehand, and this makes it awkward to use.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to provide a mixing and distributiondevice for fixing paste, particularly for multicomponent bone cement,that solves the drawbacks noted in known types.

Within this aim, an object of the present invention is to provide amixing and distribution device for fixing paste, particularly formulticomponent bone cement, that works without loss or leakage of thegas generated by the mixing of the components of the cement and allowsto extract the air from the container in which mixing occurs.

Another object of the present invention is to provide a mixing anddistribution device for fixing paste, particularly for multicomponentbone cement, that can be handled with a single hand during distributionof the fixing paste.

Another object of the present invention is to provide a mixing anddistribution device for fixing paste, particularly for multicomponentbone cement, in which the cement can flow out in a controlled andprecise manner.

Another object of the present invention is to provide a mixing anddistribution device for fixing paste, particularly for multicomponentbone cement, in which the components are mixed without producing airbubbles.

Another object of the present invention is to provide a mixing anddistribution device for fixing paste, particularly for multicomponentbone cement, that is simple and compact, easy to use, and has a limitednumber of essential components.

Another object of the present invention is to provide a mixing anddistribution device for fixing paste, particularly for multicomponentbone cement, that can be used disposably.

Another object of the present invention is to provide a mixing anddistribution device for fixing paste, particularly for multicomponentbone cement, that can be produced by way of known systems andtechnologies.

This aim and these and other objects that will become better apparenthereinafter are achieved by a mixing and distribution device for fixingpaste, particularly for multicomponent bone cement, comprising abox-like body that forms internally a receptacle that is closed in anupper region by a detachable and substantially fluid-tight lid, insidewhich means for mixing the components of the fixing paste areaccommodated, said mixing means being coupled to a piston that forms,inside said receptacle, a venting chamber toward said lid and a mixingchamber toward the bottom of said receptacle, said mixing chamber beingconnected to a channel for distributing bone cement, which is controlledby valve means, said venting chamber being instead connected to aventing channel, which can be functionally associated with suctionmeans, said device being characterized in that said mixing means areconstituted by longitudinally elongated mixing blades that are arrangedso as to slide within complementary through slots formed in said piston,a rotation pivot being further locked coaxially on said piston and beingarranged so that it can slide through a corresponding fluid-tight holeformed in said lid, said rotation pivot being associable withcorresponding rotation means that can be operated by a user during themixing of the multicomponent paste, said device further comprising ahandgrip for a single hand of the user, with which means for thetranslational motion of said rotation pivot together with said pistontoward the bottom of said receptacle are associated, said means beingactuatable with the same hand associated with said handgrip, saidventing and mixing chambers being mutually connected for the passage ofgaseous fluids.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention willbecome better apparent from the following detailed description of apreferred but not exclusive embodiment thereof, illustrated by way ofnon-limiting example in the accompanying drawings, wherein:

FIG. 1 is a perspective view of the device according to the invention inthe configuration for mixing the components of the multicomponent paste;

FIG. 2 is an exploded view of the device according to the invention;

FIG. 3 is a front sectional view of the device according to theinvention;

FIG. 4 is a perspective view of the device according to the invention,divided into two separate preassembled parts;

FIG. 5 is a perspective view of the device according to the invention inthe configuration for distributing the multicomponent paste.

WAYS OF CARRYING OUT THE INVENTION

With reference to the figures, a mixing and distribution device forfixing paste, particularly for multicomponent bone cement, according tothe invention, is generally designated by the reference numeral 10.

The device 10 comprises a preferably cylindrical box-like body 11, whichforms internally a cylindrical receptacle 12.

The cylindrical receptacle 12 is closed in an upper region by adetachable and substantially fluid-tight lid 13.

The lid 13 is internally cylindrical, with an inside diameter that hassubstantially the same dimensions as the outside diameter of thebox-like body 11.

Externally, the lid 13 is preferably cylindrical (but it can also be forexample polygonal).

Means 14 for detachable fixing to the box-like body 11 protrude from therim of the lid 13; the fixing means 14 consist of teeth 15 of thesnap-fit type, which enter by elastic deformation corresponding lockingcavities 16 formed through a perimetric annular tab 17 that protrudeslaterally from the cylindrical body 11.

Means 18 for mixing the components of the fixing paste, describedhereinafter, are accommodated inside the cylindrical receptacle 12.

The mixing means 18 are rigidly coupled to a piston 19, which forms,inside the receptacle 12, a venting chamber (not shown in the figures,since the piston 19 is shown at the beginning of its stroke) toward thelid 13 and a mixing chamber 21 toward the bottom of the receptacle 12.

The volume of the two chambers can obviously vary according to the axialposition occupied by the piston 19 inside the receptacle 12, as willbecome better apparent hereinafter.

The piston 19 has a first cylindrical portion 22, whose outside diameteris substantially equal to (at most slightly smaller than) the diameterof the receptacle 12, and a second portion 22 a, which has a conicalshape toward the bottom of the receptacle 12.

In an alternative embodiment, not shown in the figures, the vertexregion of the second conical portion 22 a has a coaxial protrusion thatis substantially elongated downward.

A rotation pivot 24 is locked coaxially on the piston 19 by way ofcorresponding locking means 23 and is arranged so that it can slidethrough a corresponding substantially fluid-tight hole 25 formed in thelid 13.

The locking means 23 comprise a first shank 26, which preferably has ahexagonal cross-section and is formed at one end of the pivot 24; twostuds 27 protrude on opposite sides from its lateral surface.

A seat 28 shaped complementarily to the first shank 26 is formed axiallyon the piston 19, and two openings 29 complementary to the two studs 27are formed on its side walls; mutual coupling occurs by elasticdeformation of the walls of the seat 28.

The rotation pivot 24 can be coupled to corresponding rotation means 30,which can be actuated by a user during the mixing of the multicomponentpaste.

The rotation means 30 are constituted for example by a crank 31, whichis detachably coupled to the free end of the pivot 24.

The free end of the pivot 24 is constituted by a second shank 32, whichpreferably has a hexagonal cross-section.

As an alternative, the means for rotating the pivot 24 can beconstituted for example by an electric motor or, as an alternative, by apneumatic motor (both of which are not shown in the figures), which arepresent in operating rooms (electric power supplies and pneumatic powersupplies are in fact both present in operating rooms) when the device isused; a chuck for coupling to the second shank 32 is associable withsaid motors.

The venting chamber is connected to a venting channel 33, which can befunctionally associated with suction means (not shown in the figures),such as for example a vacuum pump.

The venting channel 33 is constituted for example by a tube 34 thatprotrudes from the upper portion of the lid 13.

The mixing chamber 21 is connected to a channel 35 for distributing thebone cement toward the outside of the box-like container 11.

The distribution channel 35 protrudes from the bottom of the receptacle12, which has a conical shape, by means of a nozzle 36 controlled byvalve means 37, such as for example a plug valve 38.

The device 10 further comprises a handgrip 40 for one hand of a userduring the distribution of the multicomponent paste.

The handgrip is constituted for example by a pistol grip 41, which isrigidly coupled to the lid 13.

In this embodiment of the invention, the pistol grip 41 is monolithicwith the lid 13, but in alternative embodiments it is possible to usehandgrips that are detachable with respect to the lid 13 (or can beoptionally detached with respect to the box-like body 11).

Means 43 for producing the translational motion of the rotation pivot 24(with the piston 19 rigidly coupled thereto), toward the bottom of thereceptacle 12 are associated with the handgrip 40.

The translational motion means 43 are constituted, in this embodiment,by a ratchet-type mechanism, which is constituted by a plurality ofannular bulges 45 that have a sawtooth transverse profile (in which theinclination of the teeth converges toward the lid 13) and are engaged bytwo complementarily shaped teeth 46 arranged monolithically on the firstend of a first-class (centrally-pivoted) lever 47.

Elastic return means 49 that act between the lever 47 and the pistolgrip 41 are provided between the fulcrum and the second end of the lever47.

In particular, the elastic return means 49 are constituted by anelastically deformable leaf-spring element 50, which cantilevers outfrom the second end of the lever 47 toward said first end and abutsagainst the bottom of the pistol grip 41.

A collar 51 is provided on the lid 13, and the fluid-tight hole 25 isformed coaxially to the collar.

Tabs 52 for preventing reversibility of the translational motion (towardthe bottom of the container 11) of the pivot 24 are provided on thecollar 51; the tabs 52 are elastically deformable and are provided withteeth that are shaped complementarily with respect to the annular bulges45 of the pivot 24, so as to prevent the accidental upward motion of thepivot 24.

A retention element 55 is associated with the pivot 24 and has aC-shaped part designed to be coupled reversibly, by elastic deformation,to an annular groove 54 that is formed on the pivot 24 at the beginningof the annular bulges 45 and is directed toward the first shank 26.

The retention element 55 is coupled to the annular groove 54 only duringthe mixing of the multicomponent paste.

Proximate to the first shank 26 there is also an annular pocket (notshown in the figures) for accommodating a corresponding sealing gasket.

The mixing means 18 are constituted for example by mixing blades 57,which are predominantly longitudinally elongated and are arranged so asto slide inside complementary slots 58 formed in the piston 19.

The length of the mixing blades 57 is preferably equal to the internallength of the receptacle 12, and their transverse profile is curved inthis embodiment, but other profiles can be used, also depending on thetype of multicomponent paste to be mixed; the thickness of the mixingblades 57 is substantially constant, but in alternative embodiments itis also possible to use blades that have a variable thickness, forexample a thickness that increases from the side of the container 11toward the pusher piston 24.

The end of the mixing blades 57 that is directed toward the lid 13 has ahead 59 that is wider than the complementary slots 58.

The coupling of the mixing blades 57 to the slots 58 is provided withsmall passages (not shown in the figures) for the outflow of the air andgas from the mixing chamber 21 to the venting chamber.

Circumferential pockets 60 for accommodating corresponding scraper rings61 for the side wall of the receptacle 12, or alternatively sealinggaskets (not shown in the figures), are provided on the firstcylindrical portion 22 of the piston 19.

Advantageously, the device comprises accessories, such as a stand 62 inwhich it is possible to insert the box-like container 11, so that it isdirected downward, in order to mix the multicomponent paste, and acollar-funnel 63 to be arranged in abutment against the annular tab 17and is useful during the pouring of the components of the multicomponentpaste.

Moreover, the present invention comprises an extension nozzle 64 to befixed to the nozzle 36, of the syringe-needle type, so as to preciselydirect the paste during distribution on the parts to be fixed.

The invention is preferably entirely made of plastics.

The operation of the device according to the invention is as follows.

The container 11 is positioned on the stand 62 and the collar-funnel 63is fitted.

At this point, the components of the paste are poured, the collar-funnel63 is removed, and the assembly constituted by the lid 13, with thepivot 24 at the beginning of its stroke with respect to the hole 25 andthe piston 19 adjacent to the lid 13, is inserted.

In this step, the heads 59 of the mixing blades 57 abut against thepiston 19.

The venting tube 34 is connected to a vacuum pump and operated.

By way of the rotation means (crank or motor), the pivot 24 is turnedand consequently the piston 19 is turned together with the blades 57.

In this step, the locking element 55 is coupled to the annular groove54, preventing the pivot 24 with the piston 19 from moving downward.

Once the mixing step produced by the rotation of the blades 57 hasended, the user detaches the locking element 55 and grips the pistolgrip 41, beginning to press the lever 47 toward the bottom of the pistolgrip 41.

This movement produces the downward advancement of the teeth 46,consequently pushing likewise downward the pivot 24 and therefore thepiston 19.

By way of the leaf-spring element 50, the lever 47 is returned intoposition in order to allow to continue pushing the teeth 46 on theannular bulges 45, lowering the piston 19.

The fulcrum of the lever 47 is formed by a hinge that is constituted bya circular hole 47 a, which is provided on the pistol grip 41 and inwhich there is a pivot (not shown in the figures) that is rigidlycoupled to the lever.

In an alternative embodiment, the hole 47 a has an oval shape, in whichthe corresponding major axis is substantially oriented along theextension of the pistol grip 41.

The piston 19 slides on the mixing blade 57 by way of the slots 58 anduntil it makes contact with the mixed paste.

At this point, the mixing chamber is a substantially airless andgas-free environment.

At this point, by again acting on the pistol grip, the formed paste iscompressed, pushing it outward through the distribution channel 35 (theplug valve 38 has been opened beforehand).

In practice it has been found that the invention thus described solvesthe problems noted in known types of mixing and distribution device formulticomponent bone cement.

In particular, with the present invention there is no loss or leakage oftoxic gas during the mixing of the components of the cement, since anygas is continuously aspirated during the mixing step.

The mixture is thus obtained in a practically airless environment, thusavoiding the formation of air or gas bubbles.

Moreover, it is noted that all the cement that is obtained can be used,since the thrust of the piston 19 tends to push it out until it isdepleted (the piston is shaped complementarily to the bottom of thereceptacle 12).

The device is further compact and simple to use and handle.

In particular, by gripping it with a single hand one is able to directthe nozzle in the regions where the paste is to be distributed and tooperate the mechanisms for distributing said paste.

Advantageously, the invention is substantially composed of two parts: apart that is provided in an already-assembled condition and comprisesthe lid with the handgrip, the pivot and the piston with mixing blades,and a part that relates to the box-like container inside which the pasteis mixed.

In view of its limited structural complexity and of the fact that it isentirely made of plastic material, the device can be produced atextremely competitive costs and therefore used disposably.

The invention thus conceived is susceptible of numerous modificationsand variations, all of which are within the scope of the appendedclaims; all the details may further be replaced with other technicallyequivalent elements.

In practice, the materials employed, so long as they are compatible withthe specific use, as well as the dimensions, may be any according torequirements and to the state of the art.

The disclosures in Italian Patent Application No. PD2003A000139 fromwhich this application claims priority are incorporated herein byreference.

1-28. (canceled)
 29. A mixing and distribution device for fixing paste,particularly for multicomponent bone cement, comprising a box-like bodythat forms internally a receptacle that is closed in an upper region bya detachable and substantially fluid-tight lid, inside which means formixing the components of the fixing paste are accommodated, said mixingmeans being coupled to a piston that forms, inside said receptacle, aventing chamber toward said lid and a mixing chamber toward the bottomof said receptacle, said mixing chamber being connected to a channel fordistributing bone cement, which is controlled by valve means, saidventing chamber being instead connected to a venting channel, which canbe functionally associated with suction means, said mixing means beingconstituted by longitudinally elongated mixing blades that are arrangedso as to slide within complementary through slots formed in said piston,a rotation pivot being further locked coaxially on said piston and beingarranged so that it can slide through a corresponding fluid-tight holeformed in said lid, said rotation pivot being associable withcorresponding rotation means that can be operated by a user during themixing of the multicomponent paste, said device further comprising ahandgrip for a single hand of the user, with which means for thetranslational motion of said rotation pivot together with said pistontoward the bottom of said receptacle are associated, said means beingactuatable with the same hand associated with said handgrip, saidventing and mixing chambers being mutually connected for the passage ofgaseous fluids.
 30. The device of claim 29, wherein said handgrip isconstituted by a pistol grip that is rigidly coupled to said lid. 31.The device of claim 30, wherein said means for the translational motionof said rotation pivot comprise a ratchet mechanism that is constitutedby a plurality of annular bulges that have a sawtooth transverse profilein which the teeth are inclined so as to converge toward said lid, twocomplementarily shaped teeth engaging on said annular bulges and beingarranged monolithically on the first end of a first-class lever, elasticreturn means being provided between the fulcrum and said second end ofsaid lever and acting between said lever and said pistol grip.
 32. Thedevice of claim 31, wherein said elastic return means comprise aleaf-spring element, which is elastically deformable and cantilevers outfrom said second end of said lever toward said first end.
 33. The deviceof claim 31, wherein a collar is present on said lid, said fluid-tighthole being formed coaxially to said collar, tabs for preventingreversibility of the translational motion of said pivot being providedon said collar, said tabs being elastically deformable and beingprovided with teeth that are shaped complementarily to said annularbulges of said pivot so as to prevent said pivot from risingaccidentally.
 34. The device of claim 31, wherein a retention element isassociated with said pivot and has a C-shaped part designed to becoupled reversibly by elastic deformation with an annular slot formed onsaid pivot at the beginning of said annular bulges, said retentionelement being coupled to said annular slot only during the mixing of themulticomponent paste.
 35. The device of claim 29, wherein the end ofsaid mixing blades that is directed toward said lid has a head that iswider than the width of the complementary slots.
 36. The device of claim29, wherein the coupling of said mixing blades to said slots haspassages for the outflow of the air and gas from said mixing chambertoward said venting chamber.
 37. The device of claim 29, wherein thelength of said mixing blades is substantially equal to the internallength of said receptacle.
 38. The device of claim 37, wherein means fordetachable fixing to said box-like body protrude from the rim of saidlid.
 39. The device of claim 38, wherein said fixing means areconstituted by teeth of the snap-fit type, to be coupled by elasticdeformation within corresponding locking cavities formed through aperimetric tab that protrudes laterally from said cylindrical body. 40.The device of claim 29, wherein said piston has a first cylindricalportion and a second portion that has a conical shape toward the bottomof said receptacle.
 41. The device of claim 40, wherein the vertexregion of said second conical portion has a coaxial protrusion that issubstantially elongated downward.
 42. The device of claim 40, whereincircumferential pockets are provided on said first cylindrical portionof said piston in order to accommodate corresponding scraper rings forthe side wall of said receptacle or, as an alternative, sealing gaskets.43. The device of claim 40, wherein circumferential pockets foraccommodating corresponding sealing gaskets are formed on said firstcylindrical portion of said piston.
 44. The device of claim 29, whereinlocking means are provided which comprise a first shank formed at oneend of the pivot, two studs protruding from the lateral surface of saidfirst shank on opposite sides, a seat being formed axially in saidpiston and being shaped complementarily to said first shank, openingsthat are complementary to said two studs being provided on the sidewalls of said first shank, the mutual coupling of said studs and saidopenings occurring by elastic deformation of the walls of said seat. 45.The device of claim 44, wherein the free end of said pivot isconstituted by a second shank.
 46. The device of claim 45, wherein saidrotation means are constituted by a crank that is coupled detachably tosaid second shank.
 47. The device of claim 45, wherein said rotationmeans are constituted by an electric motor or a pneumatic motor, aspindle for coupling to said second shank being associable with saidmotors.
 48. The device of claim 44, wherein an annular pocket foraccommodating a corresponding gasket is formed proximate to said firstshank.
 49. The device of claim 29, wherein said venting channel isconstituted by a tube that protrudes from the upper portion of said lid.50. The device of claim 29, wherein said distribution channel protrudesfrom the bottom of said receptacle by way of a nozzle that is controlledby said valve means, which consist of a plug valve.
 51. The device ofclaim 29, comprising a stand in which it is possible to insert saidbox-like body temporarily, with its bottom directed downward, in orderto mix the multicomponent paste.
 52. The device of claim 39, comprisinga collar-funnel to be arranged temporarily in abutment against saidperimetric tab during the pouring of the components of themulticomponent paste.
 53. The device of claim 50, comprising anextension nozzle of the syringe-needle type, to be coupled to the nozzlein order to precisely direct the paste during distribution on the partsto be fixed.
 54. The device of claim 29, wherein said device is entirelymade of plastic material.
 55. The device of claim 31, wherein thefulcrum of said lever is formed by a hinge constituted by a hole, whichis formed in said pistol grip and in which there is a pivot that isrigidly coupled to said lever, said hole having an oval shape.
 56. Thedevice of claim 55, wherein the major axis of said oval hole issubstantially oriented along the extension of said pistol grip.